BROWN (US) — Women with high levels of a specific hormone produce more eggs for in vitro fertilization procedures and are more likely to get pregnant, according to a new study.

The finding about antimullerian hormone (AMH) could be useful for adjusting IVF preparations by adjusting how much follicle stimulation hormone women are receiving in the week or so before eggs are extracted for fertilization.

“Clinicians can measure AMH before or during ovarian stimulation to counsel couples about their likelihood of success,” says Geralyn Lambert-Messerlian, professor of pathology and laboratory medicine at Brown University.

“The main thrust of the paper is that you can do this test even after you have begun the preparations for initiating an IVF cycle, so it allows you to modify your treatment, at least in theory, so that your probability of success would be improved,” says co-author Andrew Blazar, clinical associate professor of obstetrics and gynecology. “Though not proven, this approach seems like a logical way to use this new information.

“What I’m hoping is that eventually it will turn out that you can now do this test in the same cycle and not wait until you have to do another cycle, which would be a considerable advantage to your patient.”

The hormone AMH is made by small follicles in the ovaries and helps regulate their growth. AMH levels in the blood are an indicator of how many follicles a woman has at the time of the hormone measurement.

For the study, the researchers measured AMH levels in 190 IVF patients, ages 22 to 44, both at the beginning and end of their preparatory course of follicle stimulation hormone treatment. They counted the eggs that were eventually harvested and then performed blood tests and later an ultrasound to confirm pregnancy.

Women with low AMH levels in the first test (less than one nanogram per milliliter) on average yielded only about six eggs, while women who had more than three times as much AMH provided about 20 eggs on average.

AMH similarly predicted whether pregnancy became established. Only about a quarter of women with less than one nanogram of AMH were pregnant five to six weeks after the IVF procedure. Among women with more than three nanograms, three in five were pregnant at that stage.

Most other studies have not found an association of AMH levels and pregnancy success though delivery, Lambert-Messerlian says.

Because some women with low AMH levels are still able to establish pregnancies, Blazar doesn’t recommend that all such women necessarily forgo an upcoming IVF procedure.